sulfátredukciós

Sulfátredukció, also known as sulfate reduction, is a biogeochemical process by which sulfate ions (SO₄²⁻) are reduced to hydrogen sulfide (H₂S) or other sulfur compounds. This process is primarily carried out by a group of microorganisms known as sulfate-reducing bacteria (SRBs). These bacteria are anaerobic, meaning they thrive in environments lacking oxygen. They utilize sulfate as an electron acceptor in their metabolic respiration, obtaining energy from the oxidation of organic matter or inorganic electron donors.

The overall reaction for sulfate reduction can be simplified as: SO₄²⁻ + 2CH₂O + 2H⁺ → H₂S + 2CO₂ + 2H₂O. In this equation, CH₂O represents an organic compound. The produced hydrogen sulfide is a gas with a characteristic rotten egg smell and is highly reactive. It can precipitate as metal sulfides, such as iron sulfide (FeS), contributing to black sediments in anoxic environments like marine sediments, wetlands, and contaminated groundwater.

Sulfate reduction plays a significant role in the global sulfur cycle. It is responsible for the removal of sulfate from aquatic environments and the generation of sulfide, which can then be re-oxidized by other bacteria or incorporated into organic matter. This process is crucial in maintaining the balance of sulfur in various ecosystems. However, the production of hydrogen sulfide can also have detrimental effects, such as the corrosion of infrastructure due to its corrosive nature and the release of toxic gas. In industrial settings, controlling or mitigating sulfate reduction is often necessary.